would you rather spend the 900 up front for an ECU or 2Kplus for a rebuild later?

im glad i premix sure it makes people look at you funny but ive had not a single engine problem :nod:

I think any of the aftermarket ECUs will get rid of codes....am I correct?

Actually it is the other way around. The engines with the most carbon build up are the least modified. Without sounding sexist, the worst engines we see are from female own cars that the owners have told us they never pushed over 4k RPM. They are shocked that the engine has failed since they never abused it. It is difficult trying to explain that puttering around town for thousands of miles and never allowing the secondary turbo to come on line is abusive. These engines have as much as a 1/16 to 3/32 full carbon coverage on the rotors. This usually leads to apex seal failure due to a "slab" of carbon falling off and initiating a cascade event. Like what Howard has pictured.

On the flip side we have had engines come in from race cars that constantly see 8k-9k RPM and the rotors are virtually clean. With or without the OMP.

We do recommend removing the OMP and running premix. Mostly because on vehicles with the PFC (or other aftermarket EMS) there are no error codes and the ECU will not go into limp mode if the OMP has failed. This leads to a quick engine failure.

Additionally cars with larger injectors should be premixing as I am not thouroughly convinced that the PFC is capable of increasing the OMP flow based off injector sizing. If you are running 1600cc injectors and it is still only flowing for 850cc then it is not supplying nearly enough oil. The only fields the PFC has for adjusting the flow rate are "Oiler vs Water temp". The AEM has a field for establishing the % increase flow for injector sizing, but the manual still recommends blocking the OMP and running premix.

Benefits aside ( and yes it looks obvious ), do you think a car running pre mix can pass emissions?

it would be very helpful for many readers of this thread if someone could explain how to fool the stock ECU into thinking the EOP was working.

i know there is someone out there w the answer...

let's hear from you.

howard

can someone post a guidline or something for premixing? amounts and type of oil etc. i premix for my vespa but i dont kno whow to do it with a car

I think i know the answer to this but i just want to be 100% clear. I have a PFC so i just need to unplug the electrical connector to stop it from pumping?

The only way is to block off the OMP and leave the OMP it in the car. This allows the stock ECU to sense the stepper motor and its motion. It is not as easy as installing a resistor, like the other solenoids. There is a progressive motion that needs to be seen or the ECU goes into limp mode. So the only way is to leave it hooked up and stashed in the engine bay, certainly not the best way of doing this.

You can do it this way or you can remove it from the car with one of our kits. http://banzai-racing.com/store/FD_13...imination.html

http://banzai-racing.com/store/media...mp_bop_kit.jpg

To add what Banzai was saying. My first Rx7's was a 88 base model automatic. I knew nothing about rotary's but I really liked the car for its lines and cleanliness. It had 80k miles and was in pristine condition.

The engine lost compression 2 weeks after I had it. WHY? The previous owner was a 60 year old man who always babied it. The addition of an automatic transmission made it that much easier for it to be limped around.

Rotaries love to rev, they run rich, and they inject crank case oil from the factory into the chamber......

This combination can create a scenario for loads of carbon.... and a dead engine.

Read this thread.... the info has been stated.

Use the search button.... the info has been stated 456,332,212 times on the forum.

Correct...

A PFC acts differently than a stock ECU. You will not get CEL's with many of the factory sensors unplugged, such as the OMP, emissions equipment, and ABS.

If you already have a PFC, just unplug it, block it, and premix it. ;)

Howard,

How many miles were on your 500+ hp engine when you took it apart, and found it to be in nearly perfect condition?

Thanks

http://www.mazdatrix.com/q-supply.htm

HC, your pics are very impressive and I agree that 2cycle is best but, for comparison sake, weren't you running 20% meth 80% pump on that engine? As you said, AI cleans carbon from the engine... Also, automatics aren't run as hard and besides, properly tuned engines like yours don't have excessively rich afr conditions which contribute to carbon deposits.

I'm using a PFC base map and its very rich, I also still have the omp working and add 8oz 2cycle per fillup (about 18gallons), my 11 heat range spark plugs fouled pretty quickly which I think was because of the combination of richness, extra oil and cold plugs. Is it detrimental to premix while the omp is still working?

When I reconnected the water injection the missfires cleaned up in just a couple of injection events.

Okay..

Any quality 2-stroke mixing oil will work fine. Castrol, Supertech, etc....

1/2 oz. per gallon of gasoline.

Dump in oil, fill tank....

This is a very good point and the water injection skews the data immensely.

Driving style has more to do with carbon build up, then anything else. Here are a couple rotors from similar engines. Both had 60K miles.

The first was modified early and was seeing weekend track time, tuned PFC, stock twins, full exhaust. Notice the thin layer of carbon:

http://www.banzai-racing.com/2008_cu...ront_rotor.jpg

This is from a completely stock car, that was never redlined. Engine locked up at a stop light. This same engine, the secondary turbo was so caked with carbon that it could not be spun. Notice the thick layers of carbon:

http://www.banzai-racing.com/schauss...ront_rotor.jpg

For comparison, here is a rotor from an engine with similar mileage, with a single turbo, v-mount, 1600cc etc, running premix:

http://www.banzai-racing.com/2009_cu...rear_rotor.jpg


This does not mean that premix is a bad thing. Again I feel that any car with upgraded injectors should be running premix. Changing the oil is critical if keeping the OMP in place, obviously.

What about changing the OMP to pull from a reservoir? Will the stock ECU still throw a code?

If you are on the stock ECU, you'll have to leave the OMP connected to the harness. Now what you actually do with the OMP, that's up to you (i.e. leave it hanging, relocate it somewhere). While I understand the issue, I don't think it's worth the effort for the majority of FD owners.

"How many miles were on your 500+ hp engine when you took it apart, and found it to be in nearly perfect condition?"

a good question.. i put 4000 mile on my 09 engine. including two dyno sessions, total of 44 2000 to 8200 4th gear runs.

i will say that my prior engine that i removed and inspected at the end of 08 was in the car for four years and 15,000 miles looked exactly the same. i have never blown an engine that i have built.

"automatics aren't run as hard and besides, properly tuned engines like yours don't have excessively rich afr conditions which contribute to carbon deposits."

agree.

"Is it detrimental to premix while the omp is still working?"

no. premix is 2 cycle oil and it's beauty is that it completely ("ashless") leaves the scene. premix is great because it works all the time.

my view is that even if you drive hard and run a trimmed fuel map the EOP should go. as i said, half of the motors i disassemble are carbon choked and the other half still have too much carbon. all of these motors had a working EOP.

another plus is...

i believe Mazda recommends against synthetic oil. it is my understanding that this is because Mazda believes synthetic oil has no place in the combustion chamber by way of the EOP. assuming this is a correct reading the elimination of the EOP allows the use of synthetic oil.

it would be absolutely great if this thread didn't veer into an "Oil" thread as oil like apex seals attracts comments like blood in the water attracts sharks. and 99.9% of the posters (including me) do not know what they are talking about.

when i get into those areas i tend to be pragmatic.

i became attracted to Mobil 1 synthetics when they came out and i was racing. Mobil 1 sponsored me as they wanted to see how their products worked in a rotary under racing conditions. my engines ran 7000 minimum to 10,000 max for 35 minute races. i ran a dry sump w 12 quarts of oil.

i was attracted initially to Mobil 1 because the USAF was having problems w the nose wheel bearings on the F-15 Eagle. they tasked Mobil to build a wheel bearing grease that would withstand the tremendous forces. which they did.

good enough for me.

i run Mobil 1 in my crankcase, Mobil 1 in my trans/diff and Mobil 1 in my wheel bearings.

everyone has a "go to" guy. my guy is Jose LeDuc. i have had the good fortune to count him as a friend for the last 6 years. Jose has never steered me wrong.

Jose runs a 2000 pound 2 rotor RX3 drag car. it has run 7.54 at 186 to date and his engines make well over 1000 rwhp. perhaps the most impressive metric is how many runs he gets from his motors before he tears them down.

when Jose tells me to do something i do it. there are only a few things where Jose says, "do this period." one of those moments concerned oil.

"howard, run nothing but 5-30 Mobil 1. period."

it works for me. the way i build my motors they have alot of oil pressure anyway so i don't need the usual racing 50 weight. my engines make 80 pounds of oil pressure at 8000 rpm. 55 pounds warm at idle.

anyway, i have this belief that synthetics are superior so i like the idea that by removing the EOP you can run synthetics in the crankcase.

that's another plus, IMO, re the EOP removal.

howard

"What about changing the OMP to pull from a reservoir? Will the stock ECU still throw a code?"

i do like this idea... and i would still premix as it works all the time. as Chris has mentioned, i don't think you would run into code problems and you would not have emission issues if you just pumped 2 cycle thru the EOP.

In one of the previous premix vs. omp threads I read something like factory set-up injects oil in the exact spot where lubrication is needed whereas premixing is not doing that as precisely as the omp set-up.

running the OMP to push 2 cycle oil is still a waste of time, the OMP only lubricates the center of the apex seal/slot.

the difference is that if you start premixing at the start of the engine's life you will notice that carbon has a very difficult time sticking to the oily rotor face. if you even start premixing later on in the engines life the engine will already be carboned up but the new carbon entering will have a more difficult time sticking to the carboned up areas because they are oily. also moving parts like apex seal slots will be able to decarbonize themselves.

don't waste your time with the OMP even if you try to convert it, it was a bad system even for the "lazy people" as i like to call them.

running premix in your fuel makes sure that ALL internal components are lubricated, not just a small spot in the seal slot.

after 25k miles on my engine i wiped the rotors off and reinstalled them, there was 0 carbon buildup on them. keep in mind i started premixing oil at the start of the engine's life.

i'm sure there is an easy way of eliminating the OMP with a potentiometer, i just have never taken the time to figure out what signal the ECU needs to see to keep it out of limp mode. if anyone knows i'm sure i can find a way of emulating the signal.

after reading the diagnosis chart it looks like the ECU simply is looking for a 1.1-4.2V input from both the stepping motor and the position sensor.

installing potentiometer on each of these 2 circuits can easily send the proper signal back to the ECU. potentiometers can be found at radio shack for about $3 each and you would need 2. the outside pins on the potentiometer are for power and ground(doesn't matter which is which) and the center pin is for the emulated signal back to the ECU. after the potentiometer is installed you simply dial it in and read the voltage coming off the center pin back to the ECU, which probably should be in the middle range somewhere around 2.5 volts to compensate for wiring and heat resistance variations.

so both the stepping motor and position sensor should have a 5 volt reference, a ground and a output back to the ECU. using those 3 wires for each it should be easy to trick the ECU even if you have a stock ECU without having to keep the POS EOP sitting in your engine bay somewhere looking out of place.

i'm just not sure why no one has bothered to figure it out as of yet.

Hmmm...

Thinking of ditching my 2 stroke engine bay tank and just making a bigger catch tank.

Let's keep the info flowing!

Easy? I don't know about easy, but possible yes. There is a thread from several years ago already with a lot of data in it when a few members started working down that path. Basically, there didn't seem to be a point to it. i.e. why go through all that trouble just to keep the stock ECU?